Feasibility of spent macroalgae biochar for removal of Acid Red 88 (AR) dye from its aqueous solution

Biochar was synthesized from Kappaphycus alvarezii reject (KR) remove the anionic azo dye, Acid Red 88 from wastewater. In this study, biochar was experimented in both batch and column adsorption studies. Batch adsorption studies were performed at varying temperature (25 – 40 °C), dosage (1 – 10 g), pH (4 – 10), time (30 – 90 min) and dye concentration (25 – 125 mg/L) respectively. From the batch adsorption studies, it was seen that maximum removal efficiency was 87.64% at 75ppm, dosage of 4 g/L, time of 60 min and pH 7 respectively. The batch adsorption experiment best fitted to Freundlich isotherm model with Pseudo-second-order kinetics indicating the adsorption to follow chemisorption mechanism process along with multilayer adsorption onto biochar’s uneven adsorption sites. It was clear from this study, that Kappaphycus alvarezii reject has the potential to serve as economical biochar as it can be utilized as an adsorbent for the efficient removal of colorants from wastewater.